Industrial truck



N. LESSER INDUSTRIAL TRUCK Feb. 7, 1950 I5 Sheets-Sheet 1 Filed April 1, 1946 INVENTOR. NATHAN LESSER ATTORNEYS N. LESSER INDUSTRIAL TRUCK Feb. 7, 1950 Filed April 1; 1946 3 Sheets-Sheet 2 INVENTOR.

N. LESSER INDUSTRIAL TRUCK Feb. 7 195% Filed April 1, 1946 3 Sheets-Sheet 3 IN V EN TOR. NATHAN LESSER ATTORNEYS Patented Feb. 7, 1950 INDUSTRIAL TRUCK Nathan Lesser, Moline, 111., assignor to Deere & Company, Moline, 111., a corporation of Illinois Application April 1, 1946, Serial No. 658,708

8 Claims. (01. 187-9) be stacked one upon the other during the transport operation. Consequently, heretofore it has been necessary to carry but one tray of parts at a time, with the result that the trucks are used to carry loads which are far below their capacity.

One of the principal objects of the present invention, therefore, relates to the provision of a truck which can be efficiently loaded with trays which can be carried and handled separately without the necessity for piling the trays one upon the other. More specifically, it is an object of the present invention to provide a truck having a plurality of load-carrying platforms or lifting forks, which can be lifted separately to pick up a plurality of separate loads without interference between one load and another. Still another object relates to the provision of a truck having a vertical guide frame, on which is mounted a pair of upper and lower lifting members or forks, which can be raised one at a time to pick up one tray of castings or the like, lift it to an elevated position, and then pick up the second load on the lower fork.

A further object relates to the provision of a truck having a pair of separate lifting members, which can be raised successively by a single power actuated lifting device. In this embodiment of my invention, the lifting device, which is preferably a hydraulic cylinder, although it is not intended to limit the invention tothe latter, is connected to one of the lifting members and operates through a portion of its range of movement to lift this member without moving the other member. When the first member has reached a certain elevation, the second lifting member is picked up by a lost motion connection between the two members, whereby both lifting members are raised simultaneously throughout the remaining portion of the range of movement of the lifting device.

Still another object of my invention relates to the provision of a truck having a pair of independently movable lifting members, such as forks or platforms, which are provided with independent lifting devices, such' as, for example, hydraulic cylinders, thereby providing for picking up 2 a load with one of the lifting forks and raising it throughout the entire range of lifting movement before the second load is lifted.

These and other objects and advantages of my invention will be apparent to those skilled in the art after a consideration of the following description, in which reference is had to the drawings appended hereto, in which Figure l is a side elevational view showing an industrial truck embodying the principles of the present invention, in a position in which it is ready to lift a tray of material, manufactured parts, or the like from the end of a roller type conveyor;

Figure 2 is a front elevational view of the industrial truck;

Figure 3 is a sectional elevational view of a portion of the truck taken along a line 3-3 in Figure 2 and showing the lifting mechanism;

Figure 4 is a plan view taken in section along a line 44 in Figure 3 showing the lifting mecha-- nism at the forward portion of the truck and also showing a portion of the roller conveyor ahead of the truck;

Figure 5 is a side elevational view of the forward portion of the truck showing the lifting mechanism in a position in which the first tray of material has been lifted on one lifting fork and the second tray of material has been moved to the end of the conveyor, preparatory to being lifted by the second lifting fork;

Figure 6 is a side elevational view of the lifting mechanism showing the truck in transport position with two loaded trays supported on the two forks, respectively;

Figure 7 is a side elevational view of an industrial truck showing a modified form of my invention in which two lifting forks are provided, each having its individual lifting mechanism;

Figure 8 is a front elevational view of the truck shown in Figure 7 Figure 9 is a sectional elevational view of the forward portion of the truck showing the lifting mechanism, taken in section along a line 9-9 in Figure 8; and

Figure 10 is a sectional plan view taken along a line III-l 0 in Figure 8 and showing the portion of the truck which includes the lifting mechamsm.

Referring now to the drawings, and more particularly to Figures 1-6, inclusive, the industrial truck is indicated in its entirety by reference numeral II and comprises a generally horizontal chassis or frame l2 carried on a pair of laterally spaced rear traction wheels l3 and a pair of comparatively smaller front wheels (4. The rear end of the truck is provided with a housing [5, in which is enclosed the power plant and the controls for the truck and for its lifting mechanism, as is well known to those skilled in the art, and which is omitted from this description in the interest of simplicity, since the present invention is not concerned with the details of the propelling mechanism. The operator's station is indicated at It behind the power plant housing 15, from which station the truck is guided by means of a steering wheel W connected to steer the truck through the rear wheels [3 in a conventional""" manner.

Intermediate the front and rear wheels [4, I3 is positioned a generally vertically disposed guide frame H, which comprises a pair of laterally' spaced upright I-beams l8, i 9, the lower ends of which are carried by the chassis I2 and the upper ends of which are interconnected by a pair of transverse tie beams 28 and a lower interconnecting beam 2| extending transversely between the I-beams l8, 19.

A pair of upper and lower lifting members 25, 26 are mounted on the upright frame I! by means providing for generally vertical shifting movement of each of the lifting members relative to the frame. The upper member 25 comprises a carriage including a pair of laterally spaced plates 21, 28 secured to a pair of blocks 29, 3!], respectively, which are interconnected by a transversely extending front plate 3| secured rigidly to the forward sides of the two blocks 29, 30, The plates 21, 28 extend rearwardly between the two I-beams l8, l9 and adjacent the inner sides of the latter, respectively. The channels, 32, 33 extending longitudinally along the inner sides of the I-beams l8, l9 serve as vertical guideways for two pairs of vertically spaced carriage supporting wheels 34, 35. One pair of vertically spaced wheels 34 is journaled on trunnions 36 extending outwardly from the plate 21, the wheels 34 being disposed within the channel 32. The other pair of vertically spaced wheels 35- are-journaled on a pair of trunnions 31 extending outwardly from the other plate 28 to position the wheels 35 within the guideway channel 33 of the I-beam IS. The upper lifting member 25 also includes a fork comprising a pair of L.-shaped arms 38, 39-spaced laterally at opposite ends of the upper carriage and having vertically extending supporting portions 40, 4| secured to the back of the front plate 3| at opposite ends thereof, respectively, and to the block 29, 30, respectively.

The lower lifting member 26' comprises a pair of laterally spaced fore and aft extending lifting arms 45, 46 disposed beneath the lifting. arms 38, 39 of the upper member 25, respectively, and having rear end portions 41, 48, which are bent upwardly and extend to a height appreciably above the upper ends of the vertical. portions 48, 4|. of the upper arms 38, 39, respectively. The two vertical supporting portions, 48' are interconnected by a transverse tie plate 49 rigidly connected thereto. A pair of carriage side plates 52, 53' are rigidly secured to the outer sides of the arm portitons 47, 48, respectively, by bolts 54 and are spaced outwardly from the vertical portions 41., 48. by means of spacer blocks 58, respectively, to position the side plates 52, 53, on the outer sides of the I-beams l8, [9, respectively. The channels 55,, 56 extending longitudinally on the outer sides of the I-beams I8, I 9, respectively, serve as guideways for two pairs of vertically spaced wheels 51, 58. One pair of wheels 51' is journaled on trunnions 59 mounted on the side plate 52 and operates within the outer channel 55 of one of the vertical beams [8, while the other pair of vertically spaced wheels 58 is journaled on trunnions 59 mounted on the other side plate 53 to position the wheels 58 within the outer channel or guideway 56 in the I-beam l9.

Thus, it is evident that the upper fork arms 38., 39 are carried on the inner carriage plates 21, 28, which are supported on the wheels 34, which engage the inner guide ways 32, 33, respectively, and thus can be raised and lowered relative to the upright frame I! and relative to the lower lifting member 25. The lower arms 45,

of' the lower lifting member 26 are carried on V the outer side plates 52, 53, which are supported in the outer wheels 51, 58 which travel in the outer guide ways 55, '56 of the I-beams l8, l9, respectively, and thus the lower member 26 is shiftable. vertically relative-to theupright frame l1- and to the upper lifting; member 25.

Both the upper and lower lifting members 25, 26 are raised and lowered by means of a power actuated lifting device in. the form of a hydraulic cylinder 65 disposed in a vertical position midway between the two vertical I-beams l8, 1.9 of the upright frame 11. The lower end of the cylinder 65 is mounted. on a support 66 on a portion of the truck frame l2 and has a piston 61 slidable vertically within the cylinder 65.. The. piston 61 is mounted on a. piston, rod, 68, which extends up.- wardly through an. opening, 69 in the upper end of the cylinder, through which. the rod 58 is slidable. The upper end of the rod 6.6 carries a journal bearing 10, within which is. journaled a transverse iackshaft H. which is provided with guide wheels 12, I3 journaled on opposite ends thereof, respectively. The wheels i2, 13 engage the vertical guidewaysl 32,, 33 along the. inner sides of the I-beams I8. [9, respectively. A pair of sprockets l4, '15 are rigidly fixed to the jackshaft H in laterally spaced. relation on opposite sides of the hydraulic cylinder 65 and a pair of lifting chains l6, 17 are trained over the. sprockets l4, 15, respectively, and have. one end of each chain connected to, brackets 18, 19'. which are fixed to a transverse bracing member 86'. which is secured to the two arms 46, ll, respectively. The other ends of the. chains 1.6, H are secured to the transverse bracing member 2],, fixed to the two upright beams. I18, 19.

Hydraulic fluid is introduced to the bottom of the cylinder 65 through a. hose connection 8| (see Figure 2). The hydraulic. control equipment for forcing the fluid into. the cylinder is controlled from the. operator's station i6 and is not described herein for it is to. be understood that any suitable conventional hydraulic mechanism. can be used. When fluid. is forced under pressure through the on connection ill. into the cylinder 65,, the piston 61 is forced upwardly therein, thereby raising the transverse. shaft TL. Since the rear ends of the chains 76, (T are anchored in fixed relation to the. transverse bar 2|, raising the bar H has the effect of raisingv the upper carriage and lifting member 25 through the. connections of the forward ends of the chains to the brackets l8, 19. The upper member 2.5 is thus raised. at a speed which, is. twice. the speed of the upward move-- 70 ment of the jackshaft. 1.1.

The lower lifting member 26 is raised through a pair of inwardly projecting shoulders 8.5, 86 near the upper ends of the vertical portions 41, 4.8. respectively, of. the. L-shaped arms 45,. 46. 76 The shoulders 86' engage a pair of outwardly projecting blocks 81, 98, which are rigidly secured to the outer sides of the carriage plates 21, 28, respectively. 1

The operation of the lifting mechanism is as follows. Normally, the two lifting forks are disposed in nested relation on the truck frame I2. When fluid is forced into the cylinder 65 below the piston 61, the latter moves upwardly, carrying the jackshaft 1| in the journal bearing and raising the upper fork 25 independently of the lower fork 26 until the blocks 81, 88 engage the shoulders 85, 86 on the lower fork member 26, after which, further upward movement of the piston 61 in the cylinder 65 causes both lifting members 25, 26 to be raised simultaneously to the upper end of the upright frame I1. The limit of upward movement of the lifting members is determined by the plates 21, 28 engaging the transverse members 20 across the top of the frame -I1.

One use for a truck of this type is illustrated in Figures 1, 4, 5 and 6, in which the truck is used to lift the trays 98, 9| containing castings, indicated at 92, from a roller type conveyor 93. The conveyor 93 comprises a pair of laterally spaced structural members 94, 95 interconnected by suitable transverse structural members 96, 91 and carried on vertical supporting legs 98. A plurality of rollers 99 are disposed transversely between the frame members 94, 95 and are rotatably supported at opposite ends, respectively, on the latter. The conveyor 93 is of the gravity type and is inclined to cause the trays 98, 9| to roll over the rollers 99 until they engage the transverse end member 91 which serves as a stop. The legs 98 are spaced forwardly from the end of the conveyor to permit the truck to drive under the latter with the arms of the lifting forks spaced later-ally from the side members 94, 95 of the conveyor, respectively.

The hydraulic cylinder is then actuated to raise the upper fork or lifting member 25 to engage the upper arms 38, 39 with the first tray 99 and to raise the latter until the blocks 81, 88 engage the shoulders 85, 86 on the lower fork 26. Further lifting movement of the hydraulic mechanism causes the upper fork 25 to raise the upper tray and also to raise the lower fork 26 by the shoulders 85, 86 into a position in which the lower arms 45, 46 pick up the second tray 9| which, in the meantime, has been moved along the conveyor 93 to the end of the latter, as indicated in Figure 5. The hydraulic cylinder can then be actuated to raise both trays 90, 9| to their upper limits of movement, to the position shown in Figure 6 in which the trays are transported to their destination.

By lowering the piston 61 in the cylinder 65, the trays can be set down at any suitable location in the reverse order. The lower tray 9| is first set upon a table or conveyor, after which further downward movement of the upper lifting member 25 brings the lower fork 26 to rest upon the frame I2, after which the upper fork 25 can be lowered away from the shoulders 85, 86 of the lower fork 26 to set the upper tray 90 upon the conveyor.

It will be noted that the blocks 81, 88 and the cooperating shoulders 85, 86 constitute a lost motion connection between the upper and lower lifting members 25, 26.

Referring now more particularly to Figures 7-10, inclusive, the modified form of my invention is in most respects similar in construction to the embodiment described above, and therefore a complete description of the modified form is not deemed to be necessary, but similar parts are illdicated by similar reference numerals in the two embodiments.

The embodiment shown in Figures 7-10 is similar to the embodiment shown in Figures 1-6 in so far as the construction of the upper and lower lifting members 25, 26 is concerned, except that the lost motion connection between the two members is omitted, thereby permitting the upper fork member 25 to be raised to the top of the upright guide frame I1 independent of the lower fork member 26. The vertical portions 41', 48' of the lower L-shaped lifting arms 45, 46 terminate in the plane of the ends of the vertical portions 49, 4| of the upper fork member, and the blocks 81, 88 are omitted entirely from this embodiment.

The difference between the two embodiments lies in the power actuated lifting mechanism for the two upper and lower forks. The lower lifting member 26 is raised and lowered in the guide frame I1 by means of a power actuated lifting device I in the form of a hydraulic cylinder disposed in a vertical position substantially centrally of the truck frame I2 and between the two upright I-beams I8, I9 of the guide frame I1, while the upper fork member 25 is raised and lowered by a second hydraulic cylinder I96 disposed in a vertical position directly behind the cylinder I05 and carried on the truck frame I2. The forward cylinder I is provided with a piston rod I01 which carries at its upper end a journal bearing I08, in which is journaled a rotatable shaft I09 extending transversely between the upright I-beams I8, I9 and having at its opposite ends a pair of guide wheels II, III, respectively. The guide wheels IIIl, III travel along the channels 32, 33 of the I-beams I8, I 9, respectively, the channels serving-as guideways to maintain the shaft I 89 in its transverse position. The shaft I I19 is provided with a pair of laterally spaced sprockets I I2, I I3, rigidly fixed thereto adjacent the guide wheels III], II I, respectively. A pair of lifting chains I I4, I I 5 are trained over the laterally spaced sprockets H2, H3 and are connected at their rear ends to the transverse frame member 2| and at their forward ends to the transverse tie beam 49 on the lower fork member 26.

The rear cylinder I86 has a piston rod I20, which is provided with a journal bearing I2I in which a transverse shaft I22 is journaled. An upright guide frame I23 is disposed behind the guide frame I1 and comprises a pair of laterally spaced channel beams I24, I25 disposed substantially vertically on opposite sides of the cylinder I96, respectively, with their channel portions I25, I21 turned inwardly. The beams I 24,- I25 are interconnected by a plate I28 between the upper ends thereof and are also connected with the upper transverse member 26 of the front guide frame I1 by connecting plates I29. The transverse shaft I22 is provided at opposite ends, respectively, with a pair of guide wheels I39 which operate in the channels I26, I21 of the guide frame I23. A pair of laterally spaced. generally triangular carriage side plates I35, I 36 are mounted on the transverse shaft I22 and are interconnected by a second shaft I31 disposed directly above the shaft I22. A pair of guide wheels I38, I39 are journaled on opposite ends, respectively, of the shaft I31 and travel in the guideways I26, I21 provided by the channels in the channel members I24, I25, respectively.

- Thus, it will be evident that the side plates was I35, I36 are interconnected by the shafts I22, I31 to form a rigid carriage frame which is mounted on the pair of lower wheels I30 and the pair of upper wheels I38, F39, which travel in the guideways I26, I21. The triangular side plates I35, I36 overhang the cylinder I05 and are interconnected by a journal bearing I40 at their forward ends. A transverse shaft I M j'ournaled in the bearing I40 and extends out wardly beyond the two side plates I35, I 36- to" support a pair of laterally spaced sprockets I45, I46. A pair of chains I4T, I48 are trained over the sprockets I45, I46, respectively, and are anchored at their rear ends on the transverse frame member 2I. The forward ends of the chains I41, I48 are connected to the transverse carriage frame member 80 on the upperfork 25'.

The operation of this embodiment of my invention is explained as follows. The upper fork 25 is raised by introducing hydraulic fluid under pressure through a hose connection I49 in the lower end of the rear cylinder I06, thereby forcing the piston and piston rod I20 upwardly in the cylinder I06, which raises the carriage side plates I36 on their supporting wheels in the guideways I26, I21, thereby raising theshaft MI and the lifting chains I47, I48 which are connected to the upper fork 25. In this manner the upper fork 25 can be lifted to the upper end of the upright guide frame I'I, independent of the lower fork 26. The lower fork 26 can be raised by introducing hydraulic fluid under pressure through a hose connection I50 in the lower end of the forward cylinder I05, thereby forcing the piston rod I! upwardly, carrying with it the transverse shaft I09 and the chains H4, H which are connected to the lower fork. The hydraulic control mechanism is not shown nor described here, but it is to be understood that any suitable conventional mechanism may be used which will control the two cylinders I05, I06 independently of one another; Obviously, however, the upper fork 25 must be raised be-- fore the lower fork is raised, since in this em'-- bodiment the forks are not designed to pass oneanother on the guide frame, although it' is to be understood that my invention is not to be limited to the particular details shown and described herein, except as set forth in the claims which follow. Furthermore, it is to be understood. that my invention is not limited to a truck having only two lifting members or forks, for it is considered to be within the scope of my invention to provide any reasonable number of vertically shiftable members on atruck.

I claim: 1. In an industrial truck, a guide namecomprising a pair of laterally spaced upright beams provided with guideways extending longitudi nally along the inner and outer sides thereof, respectively, a first carriage shiftable vertically along said frame and having'wheels' at opposite sides thereof engaging one guideway in each of said beams, a second carriage shiftable vertically along said frame and havingwheels at opposite sides thereof engaging the other guideway in each of said beams, power actuated lifting means connected with said'first carriage-forraising the latter to a predetermined height independent of said second carriage, and a part associated with said second carriage and extending upwardly therefrom and adapted to be engaged by said first carriage when the latter reaches said p're determined height, thereby causing both car'- riages tobe raised simultaneously by raisingsaid first carriage above said predetermined height;

2; In an industrial truck, a guide frame com-- prising a pair of laterally spaced upright beams provided with guideways extending longitudinally along the inner and outer sides thereof, respectively, a first carriageshiftable vertically along said frame and having wheels at opposite sides thereof engaging one guideway in each of" said beams, a second carriage shiftable vertically" along said'frame and having wheels at opposite sides thereof engaging the other guideway in each of said beams, and a pair of independently operable power actuated lifting devices connected to said carriages, respectively, for shifting' the latter relative to said frame.

3. In an' industrial truck, a guide frame comprising a pair of laterally spaced upright beams, a pair of upper andlower load carrying members mounted on said frame by means providing for vertical shifting movement of each member relative to said frame and to the other memher, a first power actuated lifting device disposed between said beams and connected to said lower m'emberfor raising and lowering the latter, and a second power actuated lifting device disposed behind said first device and having a part overhanging the latter and connected with said upper member for raising and lowering the latter.

4. In an industrial truck, a guide frame com' prising a pair of laterally spaced upright beams provided with guideways extending longitudinally along the inner and outer sides thereof, respectively, a first carriage shiftable vertically along said frame and having wheels at opposite sides thereof engaging one guideway in each of said beams, a second carriage shiftable vertically along said frame and having wheels at opposite sides thereof engaging the other guideway in each of said beams, a first power actuated lifting device disposed between said beams and connected to one of said carriages for raising and lowering the latter, and a second power actuated lifting device disposed behind said'first'device and having a part overhanging the latter and connected with the other of said carriages for raising and lowering the latter.

5. In an industrial truck, a guide frame comprising a pair of laterally spaced upright beams provided with guideways extending longitudinally along the inner and outer sides thereof, respectively, a first carriage shiftable vertically along said frame and having wheels at opposite sides thereof engaging said guide'ways on the outer sides of said beams, respectively, a second carriage shiftable vertically along said frame and having wheels at opposite sides thereof engagmg saidguideways onthe inner sides of said beams,- respectively, a first power actuated lifting device disposed between said beams and including a vertically shiftable shaft extending transversely'between the latter and having guide wheels m'ountedthereon and'engaging theguideways on the inner sides of said'beams, sprockets on said shaft, chains trained over said sprockets and'connected with said first carriage, a second power actuated lifting device disposed behind said first device and including a vertically shiftable frame overhanging said shaft, a second shaft mounted in said frame and having sprockets mounted thereon, and chains trained over the last mentioned sprockets and attached to said second carriage.

6. In an industrial truck: a guide frame including a pair of upright beams, spaced apart fl-and having vertical guideways; a transverse member having portions respectively slidably carried in said guideways; a pair of carriages arranged for vertical movement relative to the guide frame and for vertical movement relative to each other; means on one of said carriages including a transverse member normally positioned below the aforesaid transverse member and having opposite end portions respectively slidably carried in the guideways; means for raising and lowering one of the carriages at least to a limited extent irrespective of the other, including a vertically extensible and contractible device extending vertically between the beams and generally in the transverse vertical plane of the beams, means anchoring one end of the device to the guide frame, means connecting the other end of the device to the first transverse member, and means connecting the first transverse member to the second transverse member; means slidably supporting the other carriage on the guide frame for vertical movement; and means for raising and lowering said other carriage.

7. The invention defined in claim 6, further characterized in that: the beams are channel members with the open sides of the channels facing each other to provide the guideways; the transverse members have end portions slidable vertically in the channels; and the extensible 10 and contractible device is a fluid-pressure cylirider and piston assembly.

8. The invention defined in claim 6, further characterized in that: the beams are I-beams having inner and outer vertical channels, respectively, with the inner channels providing inner guideways and the outer channels providing outer guideways; the transverse members have end portions slidable vertically in the inner guideways; and the means slidably supporting the other carriage on the guide frame includes portions connected to said other carriage and received respectively by the outer guideways.

NATHAN LESSER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,297,619 Wessmann Mar. 18, 1919 1,487,571 Hurwitz Mar. 18, 1924 2,306,713 Prucha Dec. 29, 1942 FOREIGN PATENTS Number Country Date 526,063 Great Britain Sept. 10, 1940 

